1. Field of the Invention
The invention relates to a converter valve for high voltages and, in particular, a converter valve which includes groups of series-connected disk-type thyristors wherein the thyristors in each group are stacked side by side, held in place under spring pressure, and separated by heat sinks which serve at least in part to conduct current.
2. Description of the Prior Art
Converter valves of the above type can be used to form a branch of a converter and are described in the following references: ETZ-A vol. 89 (1968), pages 183 to 189, or ETZ-A vol. 93 (1972), pages 117 to 120, German Offenlegungsschrift No. 1,563,403; and the German Offenlegungsschrift No. 2,301,570. In such converter valves groups of circuit components are associated with the disk-type thyristors for protection against overcurrents and overvoltages, and drive means are provided for transmitting control pulses to the disk-type thyristors. Converters constructed from such converter valves are used for the rectification of high voltages, for example, in high-voltage DC transmission systems (HGUe systems). The converter valves may be air or oil insulated and air or liquid insulated.
For a description of the mechanical design of the groups of series-connected disk-type thyristors, which are also called thyristor columns, reference is made to the German Offenlegungsschrift No. 1,914,790 in which a thyristor column for liquid cooling is described. As above noted, the heat sinks of the thyristor columns of the valves may also be designed for air or gas cooling.
When HGUe installations are used in areas of high density, it is required that the size of the installations be kept as small as possible in order to save space. For operational reasons, this requirement can be met only if completely encapsulated valves with grounded encapsulation are employed. This precludes the use of valves which have air insulation. While oil-cooled and oil-insulated valves having their thyristor groups or thyristor columns disposed in an oil-cooled tank may be employed, the use of such valves is frequently precluded for safety reasons, as oil is a combustible medium. In addition, with such valves difficulties are encountered when repairs are necessary, since the oil filled tank must be kept opened and drained, thereby removing the installation from operation for an extended period of time.
It is, therefore, a primary object of the present invention to construct a converter valve of the above type which permits safety requirements to be met, is easy to repair and service, and has a compact structure.